Henna brows are a form of eyebrow tinting and can include 'mapping' that extends or re-shapes the brows. This technique is used to stain the skin beneath the brow hairs using high-quality henna pigment. The purpose of henna eyebrows is to cast a shadow in your eyebrows, thus creating an illusion of depth and fullness in the area. What it also does is fill in any sparseness that you might be experiencing. The good thing is that the process is completely natural as henna is a natural dye made out of a plant usually known as the henna tree.